Trip Circuit and Trip coil supervision Relay

Transcription

1 PROTECTION Trip Circuit and Trip coil supervision Relay Type VAX Customer Benefits: Trip circuit and trip coil supervision relay Choice of pre closing and post-closing supervision Simple and robust construction Only two variants based on Power Supply option: 110/220 and 24 /48 Completely dust proof by IP5X class protection Standard contact combination with 2NO+2CO, suitable for all possible application

2 PROTECTION Type VAX Trip circuit supervision relays Features Simple and robust construction Positive action without chatter Choice of pre-closing and post-closing supervision Application Post-closing or continuous supervision of the trip circuit of circuit breakers General Description Type VAX relays are of simple and robust construction. They are arranged to initiate an audible alarm and visual indication if the trip circuit of a circuit breaker fails or the breaker tripping mechanism does not operate Two versions of type VAX relays are available. Type VAX 21 relay monitors the trip circuit only when the circuit breaker is closed (post -closing supervision only) while type VAX 31 relay monitors the trip circuit continuously (both pre-closing and post-closing supervision). Both versions detect the following conditions. Failure of trip supply Open circuit of trip coil of trip circuit wiring Failure of mechanism to complete the tripping operation Type VAX 21 relay consists of two units connected. Under healthy condition with circuit breaker closed, both units are energized. If the trip circuit gets open or the trip supply fails, units A drops-off and opens contacta-1 to de-energize unit C. when the circuit breaker is open the auxiliary switch of the circuit breaker shorts contact A-1 to hold-in unit C. Type VAX 31 relay under healthy conditions with the consist of three units connected, circuit breaker closed, units A and C are energized and the operation is the same as that of type VAX 21 relays. When the circuit breaker is open unit B is also energized via the normally closed auxiliary switch of the circuit- breaker and unit C is held-in by contact B-1 Unit B will detect trip circuit abnormalities with the circuit breaker open in a similar manner as unit A with the circuit breaker closed The C unit in both the versions are delayed on dropoff by means of RC circuit for a total time of 350 to 800 milliseconds, to prevent a false alarm due to collage dips caused by faults in other circuits or during a normal tripping operations, when unit A is momentarily short circuited by the self-reset tripping relay contact. If the trip relay fails to reset possibly due to failure of the circuit breaker tripping mechanism, the alarm is initiated The alarm unit is designed to operate via pilot wires, if required.

3 Technical data Coil rating Standard voltage variants 24/48 Vdc and 110/220 Vdc. Models with specific voltage rating such as 24, 30, 48, 50, 110/125 or 220/250 volts dc are also available for ordering. Operating band 80% - 120% of rated voltage Maximum loop resistance 50 ohms for nominal alarm supply 24 to 50 V Other alarm supplies 400 ohms When rated for a 100V alarm supply the unit C will not operate at a current less than 25 milliamperes. It is therefore suit able for use with anti-corrosion negative potential blasing device. Burdens Operating time 0.35 to 0.8 sec. at 80% of rated volts (be- tween failure of trip circuit and operation of alarm contact) Thermal rating 120% of rated voltage continuous Operating indicator Hand reset operating indicator provided when required Contacts 2 Normally Open and 2 Changeover contacts available with 24/48 Vdc and 110/220 Vdc variants 3 pairs of self-reset contact one make and two break as standard with other models Insulation The relays meet the requirements of IS 3231/EC Series C-2 KV for 1 minute DC Voltage /50 110/ /250 Maximum Watts Trip Supply Alarm supply Contact Ratings Make and Carry Continuous Make and Carry for 3 Sec Break AC DC 1250VA with maximum of 5A 1250W with maximum of 5A 7500VA with maximum of 30A 7500W with maximum of 30A 1250VA with maximum of 5A 100W (resistive) 50W (inductive) with maximum of 30A

4 Dimensions and Weights Relay Case Size Maximum overall dimension Approximate Gross Height (mm) Width (mm) Depth* (mm) weight kg. VAX 21 ½ N Hor VAX 31 1 D Vert ½ N Hor *Add 76 mm for maximum length of terminal studs, alternatively, 29 mm for terminal screws The approximate gross weights given above are inclusive of cartons, mounting appendages and terminal details. The relays comply fully with requirements of IS 3231 and are suitable for use in normal tropical environments. Information Required to Order 1. Type of Relay (VAX 21 or VAX 31) 2. Aux Voltage rating

5 ALSTOM T&D INDIA LIMITED Pallavaram Works 19/1, G.S.T. Road, Pallavaram, Chennai Tel: Fax: ALSTOM T&D Worldwide Contact Centre: Tel.: +44 (0) Figure 3: Case and panel cut-out dimensions for case ½ N (all dimensions in mm) Figure 4: Case and panel cut-out dimensions for case 1D (all dimensions in mm) Alstom logo and any alternative version thereof are trademarks and service marks of Alstom. The other names mentioned, registered or not, are the property of their respective companies. The technical and other data contained in the document are provided for information only. Neither ALSTOM, its officers nor employees accept responsibility for or should be taken as making any representation or warranty (whether exp ress or implied) as to the accuracy or completeness of such data or the achievements of any projected performance criteria where these are indicated. No liability is accepted for any reliance placed upon the information contained in this brochure. Alstom reserves the right to revise or change these data at any time without further notice.